Santa Ana winds
[4] These low humidities, combined with the warm, compressionally-heated air mass, plus high wind speeds, create critical fire weather conditions, and fan destructive wildfires.
The Santa Anas are katabatic winds (Greek for "flowing downhill") arising in higher altitudes and blowing down towards sea level.
The air has already been dried by orographic lift before reaching the Great Basin, as well as by subsidence from the upper atmosphere, so this additional warming often causes relative humidity to fall below 10 percent.
[13] The end result is a strong, warm, and very dry wind blowing out of the bottom of mountain passes into the valleys and coastal plain.
These warm, dry winds, which can easily exceed 40 miles per hour (64 km/h), can severely exacerbate brush or forest fires, especially under drought conditions.
During Santa Ana conditions it is typically hotter along the coast than in the deserts,[14] with the Southern California coastal region reaching some of its highest annual temperatures in autumn rather than summer.
These low humidities, combined with the warm, compressionally-heated air mass, plus the high wind speeds, create critical fire weather conditions.
They cause cold water to rise from below the surface layer of the ocean, bringing with it many nutrients that ultimately benefit local fisheries.
When the Santa Ana winds cease, the cool and moist marine layer may re-form rapidly over the ocean if conditions are right.
More often, the high pressure system over the Great Basin, which caused the Santa Ana conditions in the first place, is slow to weaken or move east across the United States.
A related phenomenon occurs when the Santa Ana condition is present but weak, allowing hot dry air to accumulate in the inland valleys that may not push all the way to sea level.
[21] The Santa Ana winds and the accompanying raging wildfires have been a part of the ecosystem of the Los Angeles Basin for over 5,000 years, dating back to the earliest habitation of the region by the Tongva and Tataviam peoples.
[22] The Santa Ana winds have been recognized and reported in English-language records as a weather phenomenon in Southern California since at least the mid-nineteenth century.
[1] During the Mexican–American War, Commodore Robert Stockton reported that a "strange, dust-laden windstorm" arrived in the night while his troops were marching south through California in January 1847.
Symptomatic infection (40 percent of cases) usually presents as an influenza-like illness with fever, cough, headaches, rash, and myalgia (muscle pain).
The disseminated form of Coccidioidomycosis can devastate the body, causing skin ulcers, abscesses, bone lesions, severe joint pain, heart inflammation, urinary tract problems, meningitis, and often death.
[13] Per the Riverside Press-Enterprise in 2020:[35] According to research done by Orange County historian Chris Jepsen, the first reported reference to that term comes to us in 1871 from the Anaheim Gazette.
[6] Another false association is that the name is a reference to General Santa Anna of Mexico and dust clouds kicked up by his cavalry horses.
[40][41][2] The Santa Ana winds are commonly portrayed in fiction as being responsible for a tense, uneasy, wrathful mood among Angelenos.
[44] As The New York Times put it in 2003, "a dry, hot Santa Ana often symbolizes an unnamable menace lying just beneath the sun-shot surface of California life.
"[45] According to the Pasadena Public Library [Wikidata] book blog, the winds notably appear in Richard Henry Dana's Two Years Before the Mast, the Philip Marlowe story "Red Wind" by Raymond Chandler, three essays by Joan Didion ("Some Dreamers of the Golden Dream" and "Los Angeles Notebook", both included in her 1968 book Slouching Towards Bethlehem, and "Fire Season", included in her 1992 book After Henry), The Husband by Dean Koontz, White Oleander by Janet Fitch, and Less than Zero by Bret Easton Ellis.
It was one of those hot dry Santa Anas that come down through the mountain passes and curl your hair and make your nerves jump and your skin itch.
... [T]he violence and the unpredictability of the Santa Ana affect the entire quality of life in Los Angeles, accentuate its impermanence, its unreliability.
